http_server: handle socket closed exception for Python 2.7
http_server: handle socket closed exception for Python 2.7

The exception generated when closing a socket that is already closed
if different in Python 2 and Python 3. This PR updates the `except`
statement to handle both cases.

gravyboat/streamlink,chhe/streamlink,beardypig/streamlink,wlerin/streamlink,javiercantero/streamlink,streamlink/streamlink,wlerin/streamlink,gravyboat/streamlink,melmorabity/streamlink,beardypig/streamlink,chhe/streamlink,melmorabity/streamlink,back-to/streamlink,streamlink/streamlink,bastimeyer/streamlink,back-to/streamlink,javiercantero/streamlink,bastimeyer/streamlink